联合抑制Notch2和MEK/ERK通路对胃癌细胞增殖的影响

Effects of combined inhibition of Notch2 and MEK/ERK on cell proliferation of gastric cancer cells

目的探讨Notch2和MEK/ERK信号通路在胃癌细胞SGC-7901中是否存在交叉作用。方法采用体外化学合成的特异性针对Notch2的siRNA(Notch2siRNA)和丝裂原激活蛋白激酶(MEK)/细胞外信号调节激酶(ERK)信号通路的抑制剂PD98059,分别单独和联合处理体外培养的胃癌SGC-7901细胞,以转染阴性对照siRNA(control siRNA)细胞作为siRNA对照组,并设不给予任何转染的空白对照组。免疫印迹(Western Blotting)法检测磷酸化ERK1/2(p-ERK)1/2和Notch2蛋白的表达水平。比色法(MTT)检测癌细胞增殖抑制率。结果Notch2siRNA能降低蛋白Notch2的表达水平,并抑制癌细胞增殖[(38.26±1.82)%],而p-ERK的表达水平则较对照组增加。PD98059能降低p-ERK的表达水平,并抑制癌细胞的增殖[(30.05±3.16)%],Notch2水平则无明显变化,联合应用Notch2siRNA和PD98059能明显降低p-ERK和Notch2蛋白的表达水平,与Notch2siRNA或PD98059单独应用比较,显著抑制癌细胞增殖率,差异有统计学意义[(72.55±5.30)%,P<0.01]。结论特异性抑制Notch2信号通路,且抑制MEK/ERK通路可进一步增强抑制Notch2通路的抗肿瘤增殖效果,提示MEK/ERK和Notch2 2条信号通路在胃癌SGC-7901细胞中存在交叉作用。

Objective To explore whether the signaling pathway of MEK/ERK and Notch2 in gastric cancer cell SGC-7901 have some cross-talk effect.Methods Adopted Notch2 siRNA and PD98059 of the MEK/ERK signaling pathway inhibitor alone and combination both of them to culture SGC-7901 cells of gastric cancer in vitro,cells transfected with control siRNA as control siRNA group and cells without transfection were as blank control group.Phosphorylated ERK（p-ERK）and Notch2 expression were investigated by Western blotting.Cell proliferation inhibition rate was determined by MTT method.Results Compared with control groups,Notch2 siRNA reduced the expression of the protein Notch2,increased the expression levels of p-ERK,and the rates of cell proliferation inhibition were（38.26±1.82）%.PD98059 reduced the level of p-ERK and expression of Notch2 was not significantly changed.The rates of proliferation inhibition were（30.05±3.16）%.The combination of Notch2 siRNA and PD98059 significantly inhibited both p-ERK and Notch2 protein expression,and the rates of proliferation inhibition were[（72.55±5.30）%,P〈0.01].Conclusion Based on the specific inhibition of Notch2 signaling pathway,inhibition of the MEK/ERK pathway can further enhance the effect of anti-tumor proliferation.And it suggested that two signals pathway Notch2 and MEK/ERK may exist cross-talk effects in SGC-7901 cells.